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This works until you need to upgrade something, pip might upgrade to a broken set of dependencies. Or if you run on a different OS and the dependencies are diff

by remram 2y ago

This works until you need to upgrade something, pip might upgrade to a broken set of dependencies. Or if you run on a different OS and the dependencies are different there (because of env markers), your requirements file won't capture that. There are a lot of gotchas that pip can't fix.

zahlman 2y ago
> pip might upgrade to a broken set of dependencies. I'm only aware of examples where it's the fault of the packages - i.e. they specify dependency version ranges that don't actually work for them (or stop working for them when a new version of the dependency is released). No tool can do anything about that on the user's end. > Or if you run on a different OS and the dependencies are different there (because of env markers), your requirements file won't capture that. There are a lot of gotchas that pip can't fix. The requirements.txt format is literally just command-line arguments to Pip, which means you can in fact specific the env markers you need there. They're part of the https://peps.python.org/pep-0508/ https://peps.python.org/pep-0508/ syntax which you can use on the Pip command line. Demo: $ pip install 'numpy;python_version<="2.7"' Ignoring numpy: markers 'python_version <= "2.7"' don't match your environment > There are a lot of gotchas that pip can't fix. There are a lot of serious problems with Pip - I just don't think these are among them.
- remram 2y ago
  You can specify markers in the requirements file you write, not in the frozen requirements from 'pip freeze'. Because it's just a list of what's installed on your machine.
  - zahlman 2y ago
    Running 'pip freeze' creates a plain text file. You can edit it to contain anything that would have been in "the requirements file you write". "Your requirements file" may or may not capture what it needs to, depending on how you created it. But Pip supports it. (And so does the `pyproject.toml` specification.)
    - remram 2y ago
      You will need another tool to write a lock file that actually locks dependencies for more environments than your own. I don't know what you're trying to say. Pip does not support writing it. Sure, I guess if you have one Pip will "support" reading it.

by remram 2y ago

zahlman 2y ago

> pip might upgrade to a broken set of dependencies. I'm only aware of examples where it's the fault of the packages - i.e. they specify dependency version ranges that don't actually work for them (or stop working for them when a new version of the dependency is released). No tool can do anything about that on the user's end. > Or if you run on a different OS and the dependencies are different there (because of env markers), your requirements file won't capture that. There are a lot of gotchas that pip can't fix. The requirements.txt format is literally just command-line arguments to Pip, which means you can in fact specific the env markers you need there. They're part of the https://peps.python.org/pep-0508/ https://peps.python.org/pep-0508/ syntax which you can use on the Pip command line. Demo: $ pip install 'numpy;python_version<="2.7"' Ignoring numpy: markers 'python_version <= "2.7"' don't match your environment > There are a lot of gotchas that pip can't fix. There are a lot of serious problems with Pip - I just don't think these are among them.

remram 2y ago
You can specify markers in the requirements file you write, not in the frozen requirements from 'pip freeze'. Because it's just a list of what's installed on your machine.
- zahlman 2y ago
  Running 'pip freeze' creates a plain text file. You can edit it to contain anything that would have been in "the requirements file you write". "Your requirements file" may or may not capture what it needs to, depending on how you created it. But Pip supports it. (And so does the `pyproject.toml` specification.)
  - remram 2y ago
    You will need another tool to write a lock file that actually locks dependencies for more environments than your own. I don't know what you're trying to say. Pip does not support writing it. Sure, I guess if you have one Pip will "support" reading it.